Ultrasonic transducers are widely used in many different fields. Examples of ultrasonic transducers include lead zirconate titanate (PZT) transducers and capacitive micromachined ultrasonic transducers (CMUTs). A CMUT may include two electrodes arranged opposite to each other, with a transducing gap separating the two electrodes. One of the two electrodes is moveable toward and away from the other to realize an energy exchange between acoustic energy and electrical energy. For example, the CMUT may be activated by electrical signals to cause movement of the moveable electrode for generating acoustic energy. Further, impingement of acoustic energy on the moveable electrode of the CMUT may cause generation of electric signals.
In some cases, a CMUT may employ an additional bias voltage, such as when receiving acoustic echo signals for imaging purposes. For instance, the application of a bias voltage may be used to change the frequency or other transducing properties of the CMUT. As one example, the bias voltage may be a DC voltage that remains constant during imaging or other operations. Conventionally, the bias voltage may be applied by connecting a bias voltage source directly to one of the electrodes of the CMUT. However, if the CMUT fails, such as by shorting out across the transducing gap, the bias source or other circuits in the system may be damaged.